Source characterization and temporal variation of ambient metals and elements: results from a year-long monitoring with a near-real time multi-metals monitor in an industrial area of the Los Angeles Basin
Abstract
Among the components of ambient particulate matter (PM), exposure to metals and elements are of outmost concern from a toxicological perspective, mainly due to their capability to increase the redox activity of PM. Concentrations of elements in ambient PM have been traditionally quantified with time-integrated sample collection in the field followed by a laboratory analysis such as inductively coupled plasma mass spectrometry (ICP-MS) or X-ray fluorescence spectrometry (XRF). Recent technical advances in X-ray sources and detectors have resulted in the development of commercial systems capable of sampling and analyzing PM samples in sub-hourly or hourly resolution in near-real time.
A year-long continuous monitoring of multiple metals was conducted with a Cooper Xact 625 monitor in an industrial section of the City of Paramount in the Los Angele Basin, California. The Xact monitor was configured to simultaneously identify and measure 21 metals in Total Suspended Particles (TSP) with hourly time resolution. The Xact monitor was also coupled with an ultrasonic anemometer for hourly wind speed and direction measurement. Using the hourly observations over a year-long period, the temporal variations of metals including their diurnal, day-of-week, and seasonal variations were investigated. The high-time resolution measurement also enabled us to investigate the impact of exceptional events (e.g., 4th of July fireworks) on the levels of ambient metals. In order to identify and characterize sources of metals and elements, multiple linear regressions (MLR) and principal component analysis (PCA) were applied on the dataset. MLR and PCA identified several sources with distinct profiles and temporal variations. Moreover, Conditional Probability Functions (CPFs) were computed using hourly wind data for individual species as well as the PCA/MLR deduced sources of metals and were used to identify local point sources.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A41A..04H
- Keywords:
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- 0345 Pollution: urban and regional;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0368 Troposphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0394 Instruments and techniques;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3394 Instruments and techniques;
- ATMOSPHERIC PROCESSES